Answer Key
Chapter 3 – Addition and Subtraction of Decimals 3.1
Numbers with Decimal Place Value
Answers 1. .42
2. .07
3. .16
4. .87
5. .56
6. Hundredths
7. hundredths
8. Thousandths
9. Tenths
10. Thousandths
11. thousandths
12. Tenths
13. Thousandths
14. Hundredths
15. Thousandths
3.2
Numbers in Expanded Form
Answers 1. .5
2. .7
3. .1 + .01
4. .05
5. .6 + .02
6. .7 + .08
7. .3 + .04 + .005
8. .9 + .08
9. .2 + .03 + .001
10. .9 + .08 + .006
11. .3 + .03
12. .8 + .02 + .001
13. .4 + .03 + .002 + .0001
14. .8 + .07 + .003 + .0009
15. .9 + .03 + .002 + .0007
3.3
Decimals in Words
Answers 1. Five tenths
2. Eight tenths
3. Twenty-one hundredths
4. Eighteen hundredths
5. four tenths
6. Fifty-six hundredths
7. Ninety-three hundredths
8. Eight hundred and one thousandths
9. eight hundred thirty four thousandths
10. Three hundred fifty-five thousandths
11. one hundred fifty- five thousandths
12. Six hundred twenty-four thousandths
13. five thousand six hundred and twenty-three ten-thousandths 14. nine thousand seven hundred and eighty-three ten-thousandths 15. five thousand six hundred and seventy one ten-thousandths 16. two thousand one hundred and thirty- four ten-thousandths 17. one hundred twenty- three ten-thousandths 18. ninety eight ten-thousandths 19. eight ten-thousandths 20. 1 ten-thousandth
CK-12 Middle School Math Concepts - Grade 6
1
Answer Key
Chapter 3 – Addition and Subtraction of Decimals 3.4
Combinations of Decimal Money Amounts
Answers 1. $10.50
2. $5.28
3. $30.30
4. $1.25
5. $6.80
6. .35
7. $3.50
8. $1.10
9. $16.65
10. $15.60
11. $10.75
12. $5.77
13. $2.30
14. $24.00
15. $2.22
3.5
Equivalent Metric Units of Length
Answers 1. 6000 m
2. 500 cm
3. 1 m
4. 4 m
5. 9000 m
6. 2 km
7. 2 cm
8. 80 mm
9. 9 m
10. 1200 cm
11. 100 mm
12. 1,000 m
13. 6.7 km
14. 8.2 km
15. 12.5 km
3.6
Metric Unit Length Conversions
Answers 1. .1 cm
2. .5 cm
3. 1 cm
4. 1.5 cm
5. .08 m
6. .09 m
7. .11 m
8. .22 m
9. .012 km
10. .008 km
11. 2.2 cm
12. 22.5 cm
13. 54.3 cm
14. 98.7 cm
15. 123.4 cm
3.7
Appropriate Tools for Metric Measurement
Answers 1. Ruler
2. Ruler
3. Meter stick
4. Metric tape
5. kilometric odometer
6. Ruler
7. Meter stick
8. Ruler
9. Meter tape
10. meter tape
11. Kilometric odometer
12. Metric tape
13. Metric tape
14. kilometric odometer
15. Ruler
CK-12 Middle School Math Concepts - Grade 6
2
Chapter 3 – Addition and Subtraction of Decimals 3.8
Answer Key
Appropriate Decimal Units for Metric Measurement
Answers 1. cm
2. Mm
3. Meter
4. Meter
5. Km
6. Cm
7. meter
8. Cm
9. Meter
10. Meter
11. Km
12. Meters
13. meters
14. Km
15. Mm
16. Meter
17. Cm
18. Cm
19. meters
20. Km
3.9
Metric Length Comparison
Answers 1. =
2. <
3. <
4. <
5. >
6. <
7. <
8. =
9. <
10. >
11. <
12. >
13. <
14. =
15. <
3.10
Decimal Comparison
Answers 1. >
2. <
3. =
4. <
5. <
6. >
7. >
8. >
9. >
10. <
11. .2, .4, .8. .9
12. .02, .03, .04, .05, .07
13. .05, .21, .34, .55
14. .0007, .007, .07, .7
15. .032, .43, .5, .87, 1.0
16. .011, .023, .042, .055, .067
17. .022, .033, .055, .22, .55
18. .0222, .222, .321, .327, .4
19. .6, .65, .67, .678, .69
20. .00045, .0045, .045, .45, 4.5
CK-12 Middle School Math Concepts - Grade 6
3
Chapter 3 – Addition and Subtraction of Decimals 3.11
Answer Key
Decimal Rounding on a Number Line
Answers 1. 2.5
2. 2.1
3. 2.8
4. 2.9
5. 2.3
6. 2.4
7. 3.0
8. 2.0
9. 2.1
10. 2.3
11. 2.2
12. 2.0
13. 1.9
14. 2.8
15. 2.9
3.12
Decimal Rounding Given Place Value
Answers 1. .5
2. .7
3. .1
4. .24
5. .57
6. .65
7. .236
8. .567
9. .898
10. .126
11. .1
12. .01
13. .1
14. .002
15. .14
3.13
Small Decimal Rounding to a Leading Digit
Answers 1. .005
2. .007
3. .0005
4. .0002
5. .0007
6. .00003
7. .00004
8. .00005
9. .00003
10. .00005
11. .0006
12. .0005
13. .004
14. .000004
15. .00009
3.14
Large Decimal Rounding to Decimal Representations
Answers 1. 6, 000, 000
2. 46, 000
3. 678, 000
4. 400,000
5. 568,000
6. 1, 000, 000
7. 2, 000, 000
8. 20,000,000
9. 20,000,000
10. 13, 000, 000
11. 1, 000, 000, 000
12. 3, 000, 000, 000
13. 5, 000, 000, 000
14. 4, 000, 000, 000
15. 14, 000, 000, 000
CK-12 Middle School Math Concepts - Grade 6
4
Answer Key
Chapter 3 – Addition and Subtraction of Decimals 3.15
Decimal Rounding to Estimate Sums and Differences
Answers 1. 89
2. 30
3. 92
4. 66
5. 78
6. 34
7. 33
8. 8
9. 47
10. 176
11. 34
12. 56
13. 74
14. 55
15. 34
16. 77
17. 71
18. 15
19. 24
20. 12
21. 209
22. 568
3.16
Front End Estimation
Answers 1. 45
2. 59
3. 3
4. 12
5. 11
6. 4
7. 5
8. 4
9. 7
10. 23
11. 54
12. 7
13. 87
14. 92
15. 166
3.17
Decimal Addition
Answers 1. 11.2
2. 5.55
3. 8.89
4. 8.58
5. 18.98
6. 7.74
7. 4.01
8. 186.36
9. 88.77
10. 22.21
11. 91.456
12. 1.656
13. 11.741
14. 15.345
15. 27.5691
3.18
Decimal Subtraction
Answers 1. 13.65
2. 15.57
3. 21.72
4. 26
5. 29.71
6. 33.25
7. 73.89
8. 211.36
9. 543.69
10. 654.76
11. 221.11
12. 455.19
13. 33.87
14. 662.91
15. 158.43
CK-12 Middle School Math Concepts - Grade 6
5
Chapter 3 – Addition and Subtraction of Decimals 3.19
Answer Key
Mental Math to Add and Subtract Decimals
Answers 1. 6.75
2. 4.00
3. 8.00
4. 8.50
5. 12.00
6. 11.00
7. 14.50
8. 15.75
9. 10.25
10. 4.50
11. 5.50
12. 14.50
13. 23.60
14. 24.50
15. 39.75
3.20
Properties in Decimal Operations
Answers 1. Associative
2. Commutative
3. Associative
4. Commutative
5. Commutative
6. Associative
7. Commutative
8. Associative
9. Commutative
10. Commutative
11. Associative
12. Commutative
13. Commutative
14. Associative
15. Commutative
CK-12 Middle School Math Concepts - Grade 6
6
Answer Key
Chapter 3 – Addition and Subtraction of Decimals
3.21
Stem – and – Leaf Plots
Answers 1. 4
2
4
5
5
1
2
3
6
0
6
7 8
1
2
1
1
3
2
0
1
2
3
0
1
2
4
4
5
6
5
1
3
5
6
7
9
0
0
2.
3. 8
4. 1
1
3
4
4
5
CK-12 Middle School Math Concepts - Grade 6
9
9
7
Chapter 3 – Addition and Subtraction of Decimals
Answer Key
5. 1
2
3
3
2
1
2
3
3
4
7
4
0
6. 4
5
6
6
5
2
2
4
7
8
9
6
0
0
2
7
0
1
1
8
7
8
9
8
0
1
2
9
0
1
2
6
6 7
7. 3
8.
3
3
3
4
CK-12 Middle School Math Concepts - Grade 6
8
Chapter 3 – Addition and Subtraction of Decimals
Answer Key
9. 1
1
2
2
2
0
9
3
0
2
2
6
7
4
3
4
4
4 5
2
10. 3
3
4
5
5 6
0
7
2
3
8
8
9
11. 1
0
2
3
4
5
3
0
1
2
4
5
6
3
12. 42 13. 82 14. Yes 15. 70
CK-12 Middle School Math Concepts - Grade 6
9
Chapter 3 – Addition and Subtraction of Decimals 3.22
Answer Key
Stem and Leaf Plots, Range of a Data Set
Answers 1. 68
2. 97
3. 29
4. 8
5. 40
6. 32
7. 0
8. 10
9. 20
10. 40
11. 10’s
12. 40
13. No
14. True
15. False
3.23
Stem and Leaf Plots, Mean, Median and Mode
Answers 1. The average score in a data set.
`2. The middle value in a data set
3. The value that occurs the most times in a data set. 4. 68
5. 97
6. 90
7. 84.2
8. 81
9. 96
10. 29
11. 8
12. 40
13. 22.5
14. 20.5
15. None
3.24
Problem Solving Plan, Estimation with Decimals
Answers 1. $16.00
2. $14.00/$2 difference
3. Rounding
4. Approx. $4.00
5. yes
6. Approx. $2.00
7. $5.00
8. $5.00
9. No, Money amount to Front end estimation
10. Approx. $5.00
11. 2000
12. Rounding
13. No decimal amounts
14. $6.75
15. 7.00
16. 6.00
17. Rounding – decimal amounts added to dollars
CK-12 Middle School Math Concepts - Grade 6
10
